Method of manufacturing dispersion-hardened workpieces

ABSTRACT

A PROCESS FOR THE PRODUCTION OF COMPACT, MALLEABLE AND ROLLABLE METAL WORKPIECES FROM DISPERSION-HARDENED STARTING MATERIALS. COMPACT, MALLEABLE AND ROLLABLE WORKPIECES ARE PREPARED BY THE ELECTRODEPOSITION OF A METAL COMPONENT ONTO A METAL CARRIER SUCH AS A WIRE OR SHEET, THE DIMENSIONS OF THE CARRIER BEING SMALL IN RELATION TO THE VOLUME OF DEPOSITED METAL, THERE BEING ADDED TO THE DEPOSITION BATH A REFRACTORY MATERIAL AND A WETTING AGENT.

tates 8 Claims ABSTRACT OF THE DISCLOSURE A process for the productionof compact, malleable and rollable metal workpieces fromdispersion-hardened starting materials. Compact, malleable and rollableworkpieces are prepared by the electrodeposition of a metal componentonto a metal carrier such as a wire or sheet, the dimensions of thecarrier being small in relation to the volume of deposited metal, therebeing added to the deposition bath a refractory material and a wettingagent.

BACKGROUND OF THE INVENTION In known processes for the manufacture ofcompact, malleable and rollable metal workpieces from dispersionhardenedmaterials in accordance with the techniques of powder metallurgy, thereis the drawback that, despite subsequent heat treatment, the dispersedmaterial frequently deposits at the grain boundaries of the former metalpowder particles, whereas the main disadvantage of Working materialsproduced by internal oxidation or reduction lies in the frequentmicroscopic and macroscopic nonuniformity of subdivision of thedispersed material. This has as a consequence that the desireddispersion hardening effect is insufiiciently attained. It is an objectof the invention to avoid the disadvantage of these known methods.

SUMMARY OF THE INVENTION In accordance with the present invention,workpieces which are compact, malleable and rollable are producedelectrolytically from dispersion-hardened materials, by depositing ametallic component, such as a pure metal or an alloy, from anelectrolyte, upon a suitable carrier, such as a sheet or wire, Whilesimultaneously introducing a refractory component; advantageously, asuitable wetting or dispersing agent is also added to the electrolyte.

The metallic component may be any desired metal or alloy. Examples ofmetal which may be used to advantage in the practice of the inventioninclude nickel, co-

balt, columbium, vanadium, silver, and lead, while examples of suitablealloys include alloys of nickel and cobalt, containing from 10% to 50%-cobalt, or alloys of nickel and molybdenum containing from to 25%molybdenum, as well as also alloys of cobalt with nickel and tungsten,alloys of nickel with cobalt, molybdenum, tungsten and chromium, andalloys of columbium with titanium, molybdenum, tungsten and zirconium.

Refractory materials which may be employed in accordance with theinvention include the oxides, carbides, nitrides, and borides of metalssuch as aluminum, thorium, cadmium, titanium and zirconium, or mixturesthereof. Examples include A1 0 ThO TiB and ZrC. The proportion of suchrefractory material to the metal component is from about 0.5% to aboutby weight.

As a carrier material upon which the metal component is deposited, theremay be employed metal wire, sheet,

or shapes, having such small dimensions, e.g., cross section andthickness, that the carrier volume is small relative to the depositedvolume of the metal component, e.g., 22% by volume. The carrier materialis preferably identical with the metal to be deposited, or in the caseof alloys, with the main component of the alloy.

Advantageously, there may be added to the electrolyte a suitable wettingor dispersing agent, in an amount ranging from about 0.01% to about 0.5%by weight of the bath. Examples of suitable classes and types of wettingagents include: P18 of Langbein-Pfanhauser, AG 4 of Harshaw ChemicalsLtd., Manoxol of Hardmann & Holden Ltd., Empicol of Marchon ProductsLtd.

These wetting agents are typically sulfates of normal primary aliphaticalcohols containing from 8 to 18 carbon atoms, such as Empicol, orsodium salts of 2- ethylhexylsulfate or 2-ethylhexylsulfonate, or theyare sodium salts of dioctyl sulfosuccinic acid, such as Manoxol.Preferably the wetting agent is added to the electrolyte continuouslyduring the deposition.

Furthermore, the refractory material in the form of a powder is alsoadded to the electrolyte, whereby the refractory material remainsuniformly distributed throughout the electrolyte in consequence ofmovement of the electrolyte. Pore formation in the workpiece is bestprevented by mechancal means, such as, for example, by suspending thecarrier material in an electromagnetic vibrator, which is set invibration during the deposition of the metal. Another means consists insubjecting the workpiece periodically to a blow during the deposition ofthe metal, for example, by means of an electromagnet.

To achieve the desired properties, the workpiece, after the electrolyticdeposition, is compacted by extrusion, o1 forging, or explosive molding.

Typical electrolyte compositions which may be employed in the practiceof the invention are as follows:

(a) 256 g. NiSO .7H O; 45 g. NiCl .6H O; 30 g.

H3BO3 per 1 H20 (b) 300 g. PbCO 60 g. HBF g. H BO per 1 H 0 (0) 0.05 molC080,; 0.15 mol ammonium tungstate; 0.2 mol Na 'C H 0.1 mol (NH SO and2.5 mol NH per 1 H O.

The advantage of the novel method of the invention compared topreviously known methods is especially evident in the very evendistribution of the dispersed materials in the individual grains of theproduct.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following exampleillustrates the practice of the invention, but is not to be regarded aslimiting:

Example I As the electrolyte there was employed a conventional nickeldeposition bath having the following composition:

256 g. NiSO .7H O; 45 g. NiCl .6H O; g. H BO per 1 H O To this baththere was continuously added as a wetting agent the compound P18 ofLangbein-Pfanhauser, in an amount constituting about 0.04% by weight ofthe bath. As the refractory material there was introduced into the bathaluminum oxide having a particle size of less than 2 ,um, in aconcentration of 80 g./l. of electrolyte, taking care that the aluminumoxide was uniformly distributed in the bath during the electrolyticdeposition of the dispersionhardened alloys, e.g., rod material having adiameter of mm. Pore formation by gas bubbles in the workpiece wasprevented by mechanical means, namely, by electromagnetically vibratingthe carrier material during deposition. The anode was a massive nickelanode, well known in the plating art, or alternatively, small nickelpieces contained in titanium jackets. The carrier upon which depositionof the nickel took place was a formed wire of nickel, having a smallcross section, so that its volume in relation to the total depositedvolume would be small and would not influence the properties of thefinished workpiece. Wire of 1 mm. diameter was used. The nickel wasdeposited to a diameter of 50 mm. Thus, the volume of the carrier wireis V2500 that of the finished workpiece. The electrolysis was performedat a temperature of 40 C., voltage of 1-3, and current density of 0.06a./cm.

The product was compressed in an extrusion press. The compactedworkpiece was malleable and rollable and suitable for furtherprocessing.

The workpieces produced in accordance with the novel method of theinvention can be used in a wide variety of applications by reason of thewide range of properties which can be imparted to them according totheir composition. Thus, for example, the workpiece prepared from nickeland aluminum oxide, as illustrated in Example I above, exhibits a highdegree of heat resistance and at the same time an enhanced resistance towear and abrasion, so that it is particularly well suited for turbineblades, parts of combustion chambers and jet engines. A workpiece madefrom silver with refractory components is very useful for electricalcontacts.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes andadaptations, and the same are intended to be comprehended within themeaning and range of equivalents of the appended claims.

We claim:

1. Process for the manufacture of compact, malleable and rollabledispersion-hardened workpieces, comprising the steps of:

(a) introducing into an electrolytic deposition bath a carrier having avolume which is at most V3500 of the volume of the finished workpiece;and

(b) electrodepositing a metal component onto said carrier by passing acurrent through said deposition bath 4 in the presence of a refractorymaterial uniformly distributed in said deposition bath during thedepositing operation, until said volume of finished workpiece isattained.

2. The process of claim 1 in which a wetting agent is continuouslyintroduced into the deposition bath during the depositing step.

3. The method of claim 1 in which the metal component is a metalselected from the group consisting of nickel, cobalt, columbium,vanadium, silver and lead, and alloys thereof.

4. The process of claim 1 in which the refractory material is selectedfrom the group consisting of the oxide, carbide, nitride, and boride ofaluminum, thorium, cadmium, titanium and zirconium, and mixturesthereof.

5. The process of claim 1 in which pore formation by gas bubbles in theworkpiece is prevented by mechanical means during the step ofelectrodepositing.

6. The process of claim 1 in which the workpiece is further subjected tomechanical deformation for compacting the same.

7. The process of claim 1 in which the carrier is of the same metal assaid component.

8. The process of claim 1 in which said component is an alloy and saidcarrier is of the main component of said alloy.

References Cited UNITED STATES PATENTS 2,576,922 12/1951 Camin et a1.2,191,472 2/1940 Hopkins et a1. 29-528 3,057,048 10/1962 Hirakis.3,066,407 12/1962 Toensing 29-528 JOHN F. CAMPBELL, Primary Examiner D.C. REILEY, Assistant Examiner US. Cl. X.R. 204l6

